diff --git a/gnu/system/shadow.scm b/gnu/system/shadow.scm
index 0538fb1a24..7c57222716 100644
--- a/gnu/system/shadow.scm
+++ b/gnu/system/shadow.scm
@@ -321,13 +321,13 @@ (define (account-activation accounts+groups)
 <user-group> objects.  Raise an error if a user account refers to a undefined
 group."
   (define accounts
-    (filter user-account? accounts+groups))
+    (delete-duplicates (filter user-account? accounts+groups) eq?))
 
   (define user-specs
     (map user-account->gexp accounts))
 
   (define groups
-    (filter user-group? accounts+groups))
+    (delete-duplicates (filter user-group? accounts+groups) eq?))
 
   (define group-specs
     (map user-group->gexp groups))